Image Credit: Scott Gibson
More Q&A Spotlight
Clara Kim and her husband are nearly finished planning their new custom home. Only a few details remain before they can seek construction bids. But one of the remaining loose ends has major energy implications.
“We are planning to have a wood fireplace on the ground floor, within the building envelope,” Clara writes in a Q&A post at Green Building Advisor. “When it is burning, it will likely [be] burned with any glass doors on the fireplace open, for aesthetic reasons. It is only going to be used as a heat source as an occasional backup.”
Her husband refuses to consider a more efficient gas or wood stove, nor does he take kindly to her suggestion the fireplace be moved to the patio outside. No, the fireplace is going to be inside and it will be used without glass doors that would minimize heat loss.
A generation ago, that might not have raised an eyebrow. What could be more natural than a fire on an open hearth? These days, however, the energy inefficiencies of fireplaces have turned them into the equivalents of chamber pots and single-pane windows.
Kim is still holding out hope that some means can be found to minimize the energy shortcomings of her husband’s plans. Or is that an uphill fight? That’s the topic for this Q&A Spotlight.
Sorry, they’re never a good idea
Dana Dorsett gets right to the point, summing up what looks like a common point of view: “An open-hearth fireplace (with or without glass doors) is an inefficient, extremely polluting way to burn wood that has no place in a ‘green’ house,” Dorsett writes. “They are even illegal to use in some locations due to the particulate emissions problem.”
Darryl in Winnipeg adds that “burning anything…
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31 Comments
Alternatives to current wood burner?
This is a good discussion, but a lot of it is for new construction. What about if one currently has a fireplace on an exterior wall that's wood burning? If I want to make it as efficient as possible, both when using it and not, what should I go with?
Already have a top sealing damper (might not be working exactly) and am willing to put an insert in, convert to gas, etc. What's the recommendation then?
Response to Jeremy M
Jeremy,
Q. "What about if one currently has a fireplace on an exterior wall that's wood burning? If I want to make it as efficient as possible, both when using it and not, what should I go with?"
A. For the maximum efficiency, demolish the chimney and fireplace down to the foundation, and patch the wall.
If you insist on keeping the fireplace, you could seal it off permanently with concrete blocks on the interior, and then surround the entire exterior with rigid foam or mineral wool, followed by stucco. Fill the flue with a soupy grout.
If you insist on using it once a year on Christmas Eve, buy one of those fireplace balloons and use it. Create an insert out of rigid foam and thin plywood to block off the opening.
If you want to use it more than once or twice a year, you probably don't care too much about efficiency.
Better Yet
Demo the fireplace and park your new 55" flat screen tv in front of the hole. My cable company has a channel that runs a video of a burning hearth 24 hours a day during the holidays.
Voila ambience no air leakage.
The channel is actually quite nice to watch with a little Christmas music.
Is the issue Green Building or Fireplaces?
The issue seems to be which approach you are using - having a fireplace or green building. I used an ungodly expensive sealed glass fireplace in a house a few years ago 0actually, I should say the owner insisted on using it). The ACH50 for the house was only 1.5 and the builder figured that half that was the fireplace - not too bad. But otherwise aren't the two decisions somewhat opposed? Like aerobic fitness and smoking? If kids are in the picture then I would get a bit cranky about the health aspects. Just don't expect it will do much heating as pointed out above. My own house has a tight woodstove with a glass front installed in an old stone fireplace on an exterior wall. It easily heated our house (ACH50 of 5) this past winter. But my house is not new and it's not green. We made a fire in the fireplace the first night we bought the house. We froze and learned a good lesson. The next day we installed a woodstove.
If you want ultimate freedom
If you want ultimate freedom there is always anarchy
I'd like to say we all know how that fares, but i've learned not to assume common sense.
And it returns!
I'm amused to see the whole comment thread summarized with some additional thoughts. I think we'll be trying to do the following:
Renaissance Rumford 1000, with a 4" outside air duct. The guillotine glass door is actually quite nice, and may convince my husband to keep the glass door closed most of the time. That and the separate air intake should minimize the air brought in from cracks in the house. The air duct and a chimney damper of some sort can both be closed when not in use. The chimney stack is not exterior to the house, though it's adjacent to a wall (perpendicular to it) so the air intake will not have to travel far. The emissions with the door closed are 1 grams/kilogram and with the door open it's 3 grams/kilogram.
Sounds like the best compromise, Clara! (plus response to #1)
Getting the emissions down to something like the old EPA standard goes a long way toward mitigating the most egregious aspects of wood burning, and getting the effciency north of 50% means it can actually be used as a space heating appliance if need be!
For those stuck with an open hearth fireplace on an exterior masonry chimney, short of demolition you could choose to install an EPA rated air-tight woodburning insert or wood stove, and insulate the exterior side of the chimney, using only non-combustible materials. Take some pointers from some of the issues that came up on this blog:
https://www.greenbuildingadvisor.com/blogs/dept/guest-blogs/providing-outdoor-combustion-air-wood-stove
(rock wool, good, OSB or plywood sheathing plus combustible membrane air barrier = potential code violation or fire hazard )
With an insulated masonry chimney the thermal mass of the masonry is inside the thermal envelope of the house,, imroving both the comfort and efficiency of the EPS rated stove/insert. Without insulating the chimney the back of the fire-box of the fireplace becomes the lossiest few square feet of the house exterior, since with the stove/insert it's at a temperature much higher than the conditioned space, with no insulation to keep that heat inside.
Fireplaces are illegal in Phoenix/Maricopa County
Indoor fireplaces (natural wood burning) were made illegal in Phoenix/Maricopa County since 1996 in new residential construction. The reason was simple: Wood burning fireplaces pollute and they were destroying the air quality and people's health in Phoenix.
Now if you want to be a selfish jerk and hurt the environment and hurt people by installing and burning wood, then you have to live with yourself and hopefully nobody else has to live with such a miserable person like you.
Harsh? Maybe but it is the truth. If you never suffered from asthma and don't know what it's like to get an asthma attack and fight for your next breath as if it is your last. Then you would think twice about dumping all the toxins and particulates into the air from your wood burning fireplace.
The #1 pollution problem in Alaska (the last natural frontier) is guess what? WOOD BURNING FIREPLACES! Right now, the air quality in places like Anchorage is getting SO BAD from wood burning fireplaces that at times the EPA studies show the air quality in Anchorage rivals that of China. Our last natural frontier, Alaska, and one would think that the air is pure and healthy but no so in cities like Anchorage and it can all be traced back to so many people using wood burning fireplaces.
Wood burning fireplaces have no place in the modern home. Plain and simple. They pollute, they are energy hogs and destroy your homes energy efficiency, they destroy the air quality and give people health problems. But if you are a selfish SOB then I guess you will install a wood burning fireplace no matter what the facts and studies show you. If you don't have sympathy for the planet or your fellow man, then you are a person most miserable...
Coal doesn't grow on trees, Cratchit!
What would our world be without the truth-tellers? Anyway, Dana alluded to a potential solution for those with existing fireplaces, i.e., in the form of a masonry heater retrofit. The CCHRC put out a video several years ago that detailed the theory behind masonry heater efficiencies and the retrofitting process on a fireplace.
Enjoy: https://youtu.be/8xbol_-OCxQ
Peter L
For every piece of wood you don't burn, I'll burn two.
SOB's burn biomass?
LMAO
aj
SOB's burn biomass?
LMAO
aj
I'll take the heat off you Clara,
"We let folks do “non-building science” or “anti-building science” stuff all the time: 1500-cfm range hoods, unvented gas fireplaces, clothes dryers vented to the indoors, gas cooktops, attached garages... (Now these last two are bound to really rankle.)"
Please enlighten me as to why an attached garage is so "anti-building science".
Is the concern "fumes". If one runs their car for 5 minutes in the garage to warm it up then I could understand. But most start the car, open the garage door and drive it out. Lots of fresh air gets in the garage while that 50sq ft or larger opening vents while the car is driven out. Wonder how many air changes can happen in an hour thru an open garage door? Newer cars have "tight" fuel systems, no gas in carbs to evaporate.
Stored chemicals? How many people store the same or worse stuff inside the house. Basement workshops?
I always thought of attached garages as buffers between the wind and inclement outside weather.
So please enlighten me on my ignorance.
It's interesting how the
It's interesting how the topics that have the most empirical evidence coming down on one side, wood fireplaces in new construction being a good example, immediately get sidetracked to other topics, like an overabundance of government regulations which have nothing to do with the topic. Another sidetracking issue is that we are proponents of calling anyone who bought a previously constructed house with a wood fireplace an idiot. I don't think anything of the sort and I doubt anyone else does either. But Malcolm Taylor said that I "don't have a leg to stand on" because I said wood fireplaces are stupid. Well, yes, they ARE stupid and I've lived in a several houses that had them. And they were stupid then. But the difference is I never specified or drew up the plans to have those fireplaces built. So it's possible to be in possession of something stupid and still not have real culpability. I would argue that even ten years ago, (I'm being really generous here) it was not even a commonly known thing that open wood fireplaces were such poor performers as well as being bad for the environment.
That's in the past. Now it is very well known and anyone like Malcolm who is playing devil's advocate on a green building forum is simply acting like a jerk. Why should anyone on a green building forum say that in NEW construction it is perfectly OK to have an open wood fireplace? That's what Malcolm is advocating. And Malcolm, don't try to defend yourself by saying I didn't apply my thoughts to new construction. Open fireplaces in new construction goes against everything green building stands for and if you can't accept that then you do not belong on this forum trying to give advice to others. You are simply saying by your actions that you do not believe in the tenets of green construction that the rest of us believe in. Why are you here? Just trolling for the fun of it?
Response to Dirk Denzin
Dirk Denzin,
There are ways to reduce the risk of attached garages. Good strategies include:
1. Close attention to airtightness in the wall separating the garage and the house.
2. Verification of the airtightness of this wall with a theatrical fog machine.
3. Installing a time-delay exhaust fan in the garage that is wired to come on when the garage door is operated.
Researchers have found that these approaches are rarely implemented, however, so there are reasons for concern. For more information, see this Canadian study.
Thanks Martin
Thanks Martin for the info. I did notice that in the report there was no info on the amount of interface between garage and house. Whether its one common wall or common wall and ceiling. I am particularly concerned about just one common wall interface.
I will make sure that of all air tightness work done the garage area will receive the most attention.
I did notice that 4 of the 67 test homes had zero leakage between home and garage. That will be my goal.
Eric,
Does posting on a green building forum mean we are all to adopt a party line, and those that don't stick to it, such as Clara's husband or myself, are therefore fair game to be insulted? I think if you took the time to look at all my posts here at GBA you would se I am remarkably consistent. I don't believe that energy efficiency trumps other architectural values. I don't think we should look at the size and placement of windows, the shape of a house or many other features primarily through the lens of efficiency. Somehow to you that makes me a troll and a jerk. The implication being that there is a moral failure in my stance. That your single-mindedness is better than my advocating for a wider range of human values than a reductionist insistence than efficiency trumps all.
Fair enough, we disagree. But keep the childish insults out of this.
attached garages.
I design them - clients want them.
But I put HUGE NOTES on the plans stressing the necessity of a perfect air barrier between the garage and living space and follow it up with conversations between myself, the builder and subs and the owner. Insurance companies can steer you to some pretty alarming statistics about deaths from CO poisoning, some of which are attributable to attached garages and pressure differentials. I've even read stories where people opened the garage doors wide, started up the generator in the garage during a power outage, went to bed and never woke up.
Malcolm,
I agree that the
Malcolm,
I agree that the insults have to go. I'm glad we can agree on that. However, everything in home building can be seen as a mix of aesthetics, comfort, and efficiency. The task is not to go totally in one direction of the three but to find the proper mix. If it was all efficiency then we would not have windows in buildings. I'm not, nor have I ever, advocated for efficiency over all. I advocate for the proper valuation of the three.
I really don't see how having an open fireplace with all its limitations has a legitimate place in any house with aspirations to being green. It just doesn't, given the fact that the aesthetics of the new sealed gas fireplaces are so good. Wood stoves are a close second. They are really attractive. If you can't see that an old fashioned fireplace has competitors that are worthy to replace it then I don't know what to tell you. I just think you are neglecting green values completely in that valuation.
Eric,
Let me try and describe where my views on "green building" perhaps differ from that held by the majority of posters here and why. Hopefully that will assuage your fears that I am just playing devil's advocate.
I think that the prime design consideration should be building a house that the residents want to live in and form an attachment to - even if that means including some things, like open fireplaces, we may not agree with. Perhaps strangely, it was not an architect but an engineer, Joe Lstiburek who for me put it best:
"In order for buildings to last a long time, people have to take care of them. Now, in order for people to take care of them, people have to want to take care of them. And guess what? People don’t take care of ugly things. Ugliness is not sustainable. People need to want to live in a building and work in a building. Only then will they take care of it. That is why beautiful buildings are important. That is why architecture is important. I think we should have beautiful buildings. I think they should also be safe, durable, comfortable and energy efficient. Note that the energy efficiency part is at the end of the list".
Many of the green builders in the 70s and 80s made the mistake of using energy efficiency as the sole design driver of their buildings. They essentially made large solar collectors and asked people to get used to living in them because they represented some higher good. That turned out to be a dead end. If we end up having to make some compromises which make the owners happy while still achieving some of our efficiency aims , surely that is all to the good?
I also think that in all climates, except the most severe, we should not close houses up to the outside and create artificial environments sealed from their surroundings. So unlike the Passivehouse approach to hermetically sealing the enclosure against outside influence, I think we should use real "passive" strategies to increase efficiency. So for a large part of temperate North America, that means providing indoor/outdoor spaces where inhabitants can live at the ambient temperatures that surround them. In more severe heating and cooling climates there should be provision for that to occur during the parts of the year when that is possible.
Here in the PNW for instance the ambient environment doesn't vary much and you can spend a lot of your time living outdoors, provided you have shelter from the frequent rains. An appropriate house design for here should include abundant covered "rooms". In somewhere like Montreal, where the weather is more changeable, the houses should be designed to close themselves around an efficient core during the winter and expand into their surroundings during the other seasons.
In short, I don't believe in one universal set of design criteria that can work in all climates, and I guess that means I don't share some of the basic "green" tenets that others here do. Much as my views seem to rankle you, I find some of the moral high-mindedness around green building annoying. Hopefully we can put that aside and continue the dialogue.
Malcolm
Malcom,
Like you, I agree about architecture being very important but I disagree with some of your comments. Regarding Passive House methodology. It is NOT true that Passive House requires homes to be sealed against outside influence. The opposite is actually true. Passive House designs call for a larger than average amount of windows on the south side of the home. A properly designed Passive House will allow vast amounts of light, even the north end rooms, requiring less artificial lighting. Of all the homes out there being built today Passive Houses have the most natural feeling to them and bring in the outdoors due to their vast window expanses.
In regards to this topic of open wood fireplaces, it is really not an architectural issue. Yes, it can be viewed as a center focal point by having a fireplace but there are solutions out there that can create that ambiance but without the disastrous energy penalty brought on by open wood fireplaces.
Wood burning fireplace are illegal in some areas, like in the area I live in. They pollute and release particulates which hurts the air quality and people who suffer from COPD, asthma, heart disease, etc suffer when people burn wood in their fireplaces. This is real suffering and a real problem that doesn't need to be. 95% of the time a wood fireplace is burning it is used for aesthetic reasons, not the real source of heating. Why would some PURPOSELY do that and KNOWINGLY bring immediate harm to people?
You mentioned in your other post that, "For every piece of wood you don't burn, I'll burn two." That is like saying for every person I help medically, you will purposely cause medical harm to two people. That is like saying for every plastic bottle I recycle, you will purposely throw 2 bottles in the river to pollute it.
I don't get it. Why would you be on a green building forum and make such comments?
Peter L
You need to lighten up a bit. That comment was made facetiously. Look back at your post that provoked it.
We obviously have differing ideas as to what "engaging your surroundings" means if you think looking at the world through non-operable glass from a climate controlled environment where the doors are always kept shut fits that description.
I was a bit surprised at the vehemence of your opposition to fireplaces based on their environmental effect, as you have consistently been dismissive of posters who sited the possible hazards of materials or their damaging effects. Is this issue more important because it personally affects you?
Malcolm
Malcolm,
Once again you are misrepresenting the Passive House methodology. You stated, "If you think looking at the world through non-operable glass from a climate controlled environment where the doors are always kept shut fits that description." Nothing can be further from the truth about PH. Once again, the opposite of what you stated is true. PH recommend and have plenty of OPERABLE windows, usually tilt & turn. Operable windows are encouraged. Then your statement about, "where the doors are always kept shut" is once again an untrue statement. PH methology prefers for the occupants to open the operable windows to let in fresh especially at night in areas of vast diurnal temperature swings when temps drop during summer and there is little humidity in the air. This is part of the Passive Cooling or stack effect that one can flush out the interior air at night and bring in cool outside air.
You also seem to be forgetting that mechanical ventilation which is key in a PH brings in filtered and conditioned outside air 24/7. The air inside of a PH is 100x cleaner than homes where there is no mechanical ventilation and leaky walls.
The reason for my opposition to wood burning fireplaces is that unlike the debate about spray foam vs cellulose vs ICF vs straw bale. All of those elements have a purpose to increase R-Value of the home while a wood fireplace serves absolutely ZERO purpose in a new home. It has NO R-Value and serves no green building purpose. It has been clearly studied by qualified scientists to show that it does NOT belong in a energy home. When talking about wood fireplaces in new builds you are comparing apples to oranges.
We will have to agree to disagree. I believe the facts and studies are clear. Especially the recent DOE and EPA study about Alaska's air quality being at times equal to China due to the wood burning fireplaces in populated areas of Alaska. It's not up to debate. It's a fact. Wood burning fireplaces do nothing but pollute the air and cause immediate damage to the air quality and to the health of the people in the area. Wood burning fireplaces are an aesthetic element that will be a 50-100 year energy penalty on the home which equals to having a 5 foot hole in your wall 24/7/365 for the life of the home.
Malcolm and Peter,
I think
Malcolm and Peter,
I think the tone of the comments are more of the problem than the content. And I accept some responsibility in the derisiveness of my own tone in the original thread that inspired this thread (horse and buggies, cowboys, and all that). I think it may have got people's attention in ways I didn't intend.
Malcolm, I get your point about getting people to love their home. However, I also think that form follows function. Taste isn't something immutable. It follows from facts of the world in which one lives. My own feeling is that the voluptuous Rubinesque women portrayed in paintings from the middle ages came from the fact that it was hard to be, shall we say, on the heavy side. That was exotic then and portrayed healthiness in times of famine and starvation. You could say that people were trained to see beauty in those voluptuous women.
I think the same is true now in that it's hard to be thin in a world where there are McDonalds everywhere. People admire thinness because it is so hard to achieve. I think you probably can see where I'm going. You are beholden to your clients. I understand that. But perhaps you have been in some way "captured" by them in ways that aren't healthy for the planet. Maybe your clients need to be educated about a more up to date way of seeing beauty. Something that is more appropriate to the planet in its present state...
Eric,
I have never put a fireplace in a house I've designed or built, and I would do my best to dissuade any client against doing so. I agree they are dumb. I don't think the circumstances the Op described warranted the response she got, nor do I think it would have been the end of the world if they had opted for an open hearth. What was needed was a bit of persecutive. The Op's decision is absolutely inconsequential to any of the pressing issues that face us. It wasn't worth getting all worked up about.
Our 1947 Maryland (climate zone 4) home has a masonry fireplace. I think the "electrify everything" idea is the best way to address climate change. (Debatable, I know, but that's another debate.)
That seems to leave me with these backup options on the rare occasion that the power goes out for an extended period in the winter: battery storage or the fireplace. (Other options like a standalone vented wood or propane stove seem way too costly and elaborate for the need.) I need a plan to keep my pipes from freezing in an all-electric home. That's why how to get a fireplace to heat a home in an emergency power outage seems like a green home question to me.
Given the rare occasions this backup will be used, efficiency doesn't matter much at all. I'm dubious that I should buy a battery backup for this, unless it's going to pay for itself in other ways like time-of-use rate / grid management. Someday an electric vehicle might be the answer, but I just bought a car a few years ago, and the electricity in my current Honda Clarity plug-in hybrid would only run a couple of space heaters for six hours at best.
For the fireplace, I searched online expecting to find an apparatus like this: Open a nearby window, put the rectangular device in the window opening, and then run the attached large duct tube from there to the front of the fireplace. Ugly as heck, but the tube collapses and you store it in a closet when you're not using it.
Anyone seen a product like that? Do I have to create this myself?
With that better venting and proper fire construction (using a Grate Wall of Fire or Titan-brand vertical fireplace grate with a fireback), would this on balance heat the house, rather than drawing more cold air in through house leaks than the fire contributes?
I think your air intake plan would work well, and I think you do need to make it yourself. I think the duct would need to be pretty large to be sure the air comes in there, not in leaks elsewhere. I'll guess 6" as a minimum.
As for how well that works as a backup plan, I don't know, but I suspect it would work fine to keep the house warm enough for people to be comfortable and safe for a while. I'm less confident about how well it would prevent pipes freezing far from the fireplace--it could even make things worse by sucking in cold air through cracks in the basement near pipes. But Maryland isn't that severe a climate so you might be fine. During an extended outage, you might want to also leave faucets dripping and monitor the temperature in the far corners of the basement or upstairs bathrooms to avoid freezing.
Thanks Charlie! Good point about the farther pipes -- I'm getting a blower-door test soon and will consider that.
I realize now I left out the most common backup plan -- an outdoor generator! I never thought I would own one of those things, so I wasn't even keeping it in mind. Still, seems like my fireplace plan -- if it would actually work -- would be a lot cheaper than buying and wiring a generator into the circuit panel so my heat pump and/or water heater could run.
John,
Before settling on that option I'd try a dry run and see how well the fireplace alone is able to warm the house.
Several years ago we had a rare snowstorm here on Vancouver Island that took out the power for five days and stranded one of my neighbours elsewhere. I tried to keep their house warm with the open fireplace - something that was quite difficult as the inability to damp down the fire meant it consumed vast amounts of wood, and needed frequent re-fueling. Despite this the interior temperatures, especially in the more remote rooms, barely budged - and that's here in the temperate PNW.
John,
I agree with Malcolm. A fireplace is designed to heat people standing (or sitting) directly in front of it. A fireplace is not designed to heat a house.
The faster the fire burns, the more cold outdoor air is introduced into the house.
Martin,
The Scots describe the effects of having to sit too close to a fireplace to stay warm as leading to Corned Beef Shins.
Wow! We've brought out the fire-eaters on both sides....My view is that certainly, a fireplace is not a way to heat a home, and probably won't be much use for back-up heating either. But here in New England, it's pretty hard to find many clients that don't want a fire place in a new home, no matter how energy efficient it may be on other fronts. Certainly that fireplace will be an efficient as possible Rumford design and have an outside air (with a damper to close it off) and the chimney will be located within the building envelope. And guess what? That fireplace is pretty much for general ambience whether burning a fire or not. Chances are someone makes a fire an evening or so a week during the winter months. Does it add to pollution? Sure, but so do the couple of cars they drive every day year round, and the six burner gas range they can't do without, and the gas grill outside. But as someone said above, a home that is loved, will be a home that is maintained, and taken care of, and will last many generations.
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